Dry powder fire extinguisher



April 8, 1952 E. H. HANSEN 2,592,029

DRY POWDER FIRE EXTINGUISHER Filed April 14, 1950 Patented Apr. 8, 1/952UNITED STATES PATENT OFFICE 2,592,029 par rownEa man ExrlNcursHEa EdwardH. Hansen, Elkhart, Ind., asslgnor to Elkhart Brass ManufacturingCompany, Inc., Elkhart, Ind., a corporation of Indiana Application April14, 1950, Serial No. 155,817-

. 5 Claims.

This invention relates to portable fire extinguishers and refers morepiirticularly to the type of chemical fire extinguisher which employs adry powder extinguishing agent and an inert gas under pressure fordelivering the agent to the site of the fire.

The most compact type of dry powder re extinguisher is that in which' avcartridge or bottle of inert gas (usually carbon dioxide) is supportedinside aV closed substantially cylindrical tank or vessel containing acharge of a powdered extinguishing agentv such as sodium bicarbonate.-fw

Inert gas under high vprcsliire, escaping from the discharge port of thecartridge, carries the powder out of an outlet in the; vessel in asteady stream which continues as long as the inert gas has substantialpressure. Aiire extinguisher of this type is shown in the patent toMeigsl No. 1,987,785.

In past nre extinguishers of this type, however, it has not beenpossible to regulate the rate of escape of inert gas from the cartridge,and consequently it -has not been possible to regulate the rate ofdischarge ofthe extinguishing agent or to interruptits flow. Thisdisadvantage was especially serigus where the extinguisher was neededfor 4fighting a number of small, dispersed tires, since Athe ow ofextinguishing agent could not be interrupted during the periods when theextinguisher was being moved from one fire to another, and consequentlya valuable portion of Vthe charge was wasted. Moreover, the entirecharge of such an extinguisher was dissipated in lighting a single fire,no matter how smalhand it was then unavailable for any further use untilrecharged.

By contrast, it is an object of this invention to provide a portablefire extinguisher of the dry chemical type in which the rate ofdischarge of the extinguishing agent may be controlled or its flowinterrupted a'sdesircd.

Another object of this .invention resides in the provision of a portableilre extinguisher of the dry chemical type which isA compact and easy tooperate so that it may be readily brought to the site of a re andquickly put into action.

With the above and other objects in view, which will appear as thedescription proceeds, this invention resides in the novel construction.combination and arrangement of parts substantially as hereinafterdescribed and more particularly defined by the appended claims, it beingunderstood that such changes in the precise embodiment of thehereindisclosed inven- 2 tion may be made as come within the scope orthe claims. A

The accompanying drawing illustrates two complete examples of thephysical embodiment of the invention constructed according to thebestmodes so far devised for the practical application of the principlesthereof, and in which:

Figure 1 is a vertical sectional view through a fire extinguisherembodyingthe principles of this invention;

Figure 2 is a detail sectional view. upon an enlarged scale, of thevalve mechanism of the fire extinguisher of this invention; and

Figure 3 is a detail sectional view of a modified embodiment of saidvalve mechanism.

Referring now more particularly to the accompanying drawing, in whichlike numerals designate like parts, the numeral 5 indicates generally asubstantially cylindrical tank or vessel adapted to contain a charge ofdry powder re extinguishing agent such as sodium bicarbonate and havingan outlet 6 at its bottom through which the powder is adapted to bedischarged. A ilexible hose 1, connected to the outlet, enables thedischarging stream of chemical to be accurately directed upon a fire.

The tank 5 is preferably made of sheet rmaterial, in conformity withconventional with conventional practice, and a heavier externallythreaded neck 8 is bonded to its open top to accommodate an internallythreaded cap 9 furnished with a ring-like handle II to facilitateremoval and replacement of the cap for charging the extinguisher and toenable it to be readily carried from place to place. A resilient annulargasket l0, compressed between the top of the cap and the rim of the neckinsures a gas-tight seal between them.

A Well-like cylindrical carrier I2 is removably supported within thevessel from the top thereof by means of a ange I2' resting on the lugs8'. This carrier is easily inserted into the vessel after the vessel hasbeen charged with powder and when in position provides a receptacleforan inert gas bottle or cartridge I3 inserted therein in an uprightposition, with its discharge port I4 lowermost. The carrier issubstantially longer than the cartridge so that the cartridge may havelimited axial movement and it has a diameter somewhat greater than thatof the cartridge to allow gas escaping from the discharge port` to passupwardly around the cartridge and out of the carrier or receptacle, intothe tank, through outlets I5 in the wall of the receptacle, near the topthereof.

A row of circumferentially spaced spacer studs or bumpers I6 hold thecartridge centered in the receptacle and allow it to move freely up anddown therein.

It is to be noted that the gasket I is suiliciently wide to overlie theouter marginal edge portion of the upper surface of the ilange I2 aswell as the rim of the neck 8 to thus provide a completely gas-tightseal for the top of the vessel.

The valve by means of which escape of inert gas from the cartridge iscontrolled comprises a resilient gasket I9 of rubber or neoprenef whichis aflixed to the ilat bottom of the carrier I2 in position to cooperatewith a shoulder or rim 20 around the discharge port of the cartridge. Itwill be seen that the gasket and shoulder together deiine an annularoutlet valve through which inert gas from the cartridge must escape inorder to pass upwardly around the cartridge and thence out of the portsI in thhe wall of the carrier I2.

One end of a coiled compression spring 2| rests on the bottom of thecarrier I2 and its other end bears against a flange 22 on the cartridgeto bias the cartridge upwardly, against its own weight, to a position inwhich the valve is wide open. A drive screw 23 threaded through thecenter of the cap 9 is adapted to drive the cartridge downwardly,against bias of the spring 2|, toward the valve-closed position. Thedrive screw is provided with a convenient handle 24, accessible at thetop of the tank, and its lower or inner end has a suitably adaptedsocket 25 which rmly engages the hemispherical top of the dischargecartridge.

A tapered puncturing pin 26 is mounted on the bottom of the carrier inposition to engage the frangible seal 21 which normally closes thedischarge cartridge, to puncture the seal when the cartridge is drivendown to the position in which its shoulder or rim 20 completely engagesthe gasket I9 to closes the valve mechanism. The pin is provided withlongitudinal grooves or flutes 28 to permit the instantaneous escape ofgas as soon as the drive screw is retracted suiliciently to enable thespring to raise the cartridge enough to open the valve defined by theshoulder 20 and the gasket I9.

The frangible seal 21 of the cartridge or bottle shown in Figure 2comprises a disc or membrane of relatively soft metal which is clampedbetween an annular ledge or shoulder 29 on the discharge port of thebottle and an apertured plug 30 threaded into the mouth of the outlet.

' In the modified embodiment of the valve mechanism shown in Figure 3the shoulder 29' is relatively Wide and is chamfered at its innerperiphery as at 32. The chamfered portion of the shoulder thus backs upthe ruptured edge of the seal disc 21', which then serves as'a valveseat capable of cooperating with an uniluted tapered puncturing pin 26'to provide a needle valve.

It will be seen that in this embodimentof the invention no resilientgasket is required in the lbottom of the well-like receptacle or carrierI2 since the puncturing pin, together with 'the edges of the frangibleseal after the latter has been ruptured, functions as a valve mechanismwhereby the discharge of gas from the cartridge may be regulated orstopped completely.

Operation of the extinguisher of this invention is exceedingly simple.In order to ll it with powder the cap 9 is unscrewed from the top of thetank, and the carrier I2 is lifted -outof the 4 tank to enable a chargeof powder to be poured into the tank. The carrier is then replaced, afilled gas cartridge inserted therein and the cover is firmly screwedback into place to close the vessel.

In operating the extinguisher it is carried as near to the site of theiire as possible and then the drive screw 23 is screwed down by means ofthe handle 24 until the puncturing pin 26 ruptures the frangible seal ofthe cartridge. In each of the embodiments the drive screw is thenretracted, by turning it in the opposite direction, until a satisfactoryrate of flow of the re extinguisher agent from the hose outlet isestablished. The ow of powder may be diminished at any time or evenstopped entirely by turning the drive screw inwardly so as to push thecartridge down toward the closed position of the valve.

From the foregoing description taken together with the accompanyingdrawing it will be readily apparent that this invention provides acompact portable re'extinguisher of the dry chemical type wherein therate of escape of inert gas from the cartridge may be regulated orstopped at will to thus enable complete regulation of the rate ofdischarge of powder from the extinguisher.

What I claim as my invention is:

1. A valve structure for controlling the discharge of gas from acartridge of the type having an outlet at one of its ends normallyclosed by a frangible seal, said valve structure comprising: a valvebody including a hollow receptacle closed at one end and open at theother end to enable a gas cartridge to be freely insertedendwise'thereinto With its outlet facing the closed end of thereceptacle, and a cover closing said open endof the receptacle; thevalve body having escape ports therein through which gas in the interiorof the receptacle may escape to the exterior thereof; a resilient gasketinside the -closed end of the receptacle cooperable with the outlet ofthe cartridge to define a valve through which gas may' escape from thecartridge into the interior of the receptacle; spring means in theclosed end of the receptacle to bias the cartridge toward the coveredend of the receptacle, away from said gasket, to a valve open position;a manually operable drive screw threaded in the cover and extending intothe receptacle to bear against the adjacent end of a cartridge in saidreceptacle, said screw being cooperable with the spring means throughthe cartridge to effect regulation of said valve; and a puncturing pinimmovably carried by the valve body inside the receptacle, at the closedend thereof, with its point projecting through said gasket toward thecovered end of the receptacle, for rupturing the frangible seal on thecartridge when the latter is driven against the puncturing pin by saiddrive screw.

2. A valve structure for controlling the discharge of gas from acartridge of the type having an'outlet at one of its ends normallyclosed by a frangible seal, said valve structure comprising: a valvebody including a hollow receptacle closed at one end and open at theother end to enable a gas cartridge to be freely inserted endwisethereinto with its outlet facing the closed end of the receptacle, and acover closing said open end of the receptacle; the valve body havingescape ports therein through which gas in the interior of the receptaclemay escape to the exterior thereof; a resilient gasket inside the closedend of the receptacle cooperable with the outlet of the cartridge todene a valve through which gas may escape from the cartridge into theinterior of the receptacle; spring means in the closed end of thereceptacle to bias the cartridge toward the covered end of thereceptacle, away from said gasket, to a valve open position; manuallyoperable means carried by the cover, having a part inside the receptaclemovable toward and from the closed end thereof and engageable With theadjacent end of a cartridge in the receptacle to hold the cartridge indifferent positions of endwise adjustment relative to the receptacle, sothat said cover carried means is cooperable with the spring meansthrough the cartridge to effect regulation of said valve; and apuncturing pin immovably carried by the valve body inside thereceptacle, at the closed end thereof, with its point projecting throughsaid gasket toward the covered end of the receptacle, for rupturing thefrangile seal on the cartridge when the latter is driven against thepuncturing pin by said cover carried means.

3. The valve structure defined in claim 2 further characterized by theprovision of longitudinal grooves in the puncturing pin to facilitateescape of gas from the cartridge when the frangible seal is ruptured bythe pin.

4. A valve structure for controlling the discharge of gas from acartridge of the type having an outlet at one of its ends normallyclosed by a frangible seal, said valve structure comprising: a valvebody including a hollow receptacle closed at one end and open at theother end to enable a gas cartridge to be freely inserted endwisethereinto with its outlet facing the closed end of the receptacle, and acover closing said open end of the receptacle; the valve body havingescape ports therein through which gas in the interior of the receptaclemay escape to the exterior thereof; spring means in the closed end ofthe receptacle to bias the cartridge toward the covered end of thereceptacle; manually operable means carried by the cover having a partinside the receptacle movable toward and from the closed end thereof andengageable with the adjacent end of a cartridge in the receptacle so asto cooperate with the spring means in providing for endwise adjustmentof the cartridge in the receptacle; and a puncturing pin immovablycarried by the Valve body inside the receptacle, at the closed endthereof, said puncturing pin having a substantially conical pointprojecting toward the covered end of the receptacle for rupturing thefrangible seal on the cartridge when the latter isfdriven against thepuncturing pin by said cover carried means, and said conical pointrestricting the punctured opening by an amount depending upon theposition in Which the cartridge is held jointly by the cover carriedmeans and said spring means.

5. The valve structure set forth in claim 4 wherein the manuallyoperable means carried by the cover comprises a drive screw threaded inthe cover and extending into the receptacle to bear against the adjacentend of a cartridge in said receptacle.

EDWARD H. HANSEN.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS

